The storage system disclosed in Patent Citation 1, for example, is known as a storage system comprising a plurality of processor units.
In this type of storage system, an owner right is granted to each processor unit for one or more LDEV of a plurality of LDEV. As used here, “LDEV owner right” is the right to access the LDEV. An “LDEV” is a logical storage device managed by the storage system.
For example, it is supposed that the storage system has processor units #0 and #1, and manages LDEV #0, #1 and #2, and that the LDEV #1 owner right has been granted to processor unit #0. This storage system is such that when the storage system receives an I/O (Input/Output) command for LDEV #1, the processor unit #0, which has the LDEV #1 owner right, processes this I/O command.
Centralizing the owner rights for a plurality of LDEV in one processor unit intensifies the load on this processor unit. According to Patent Citation 1, the load on each processor unit is monitored, and owner rights change among the processor units in accordance with the results of this monitoring.